Enrique Peña Nieto, the president of Mexico, came to power in 2012 promising a change of strategy in the country's war on drugs.

Instead of following his predecessor's path of hunting down the top leaders of drugs cartels, who control an industry worth an estimated 3 to 4 per cent of Mexico's $1.2 trillion annual GDP - totalling as much as $30 billion- the Mexican leader promised a different method.

He vowed to switch the focus away from military intervention, and instead look at the root socioeconomic causes of the violence: the poverty that makes working for the cartels so attractive, the lack of employment that pushes young people into their ranks, and the lack of trust in the authorities that makes reporting crime so rare.

Yet in the three years since he came to power, Mr Peña Nieto has indeed followed his predecessor's path, in the sense that his armed forces have killed or captured a series of Mexico's "most wanted" drugs kingpins.

In 2009 the attorney generalpublished a list of the 37 most wanted drug traffickers, 33 of whom have now been detained or killed. Felipe Calderon, the previous president, oversaw the capture of 22 of them in his six-year term. Mr Peña Nieto, mid way through his term, can claim the scalps of nine. Two more have died in battles with rival gangs.

Of the four that remain at large, two are from the Sinaloa cartel. Ismael Zambada García, known as El Mayo, took the reins from Chapo Guzman following his arrest in February 2014, and was probably the most wanted man in the country - until Guzman's 2015 escape.

Juan José Esparragoza, alias El Azul, is another Sinaloa capo - although there are reports that he died from a heart attack in June 2014.

The other two still at large are from the Zetas - Eduardo Almanza - and the Juarez cartel, Juan Pablo Ledesma, known as El JL.

Here are some of the most high-profile arrests under the current president.

Omar Treviño Morales is escorted by soldiers following his arrest (Reuters)

Omar Treviño Morales, 44, wascaptured near Monterreyin the town of San Pedro Garza García – the wealthiest municipality in Latin America.

Seized from a luxury modern gated home at 4am, he was taken without a shot being fired - despite being one of Mexico's most wanted men. The US Drugs Enforcement Agency (DEA) put a $5 million (£3.3 million) bounty on his head, while the Mexican authorities had offered a 30 million peso (£1.3 million) reward for information leading to his arrest.

Treviño Morales took over control of the Zetas in July 2013, when the previous leader - his brother Miguel - was captured. Until that point he had led the gang's operations from Piedras Negras, upstream on the Rio Grande from their main stronghold of Nuevo Laredo.

Treviño Morales was born in the city on January 26, 1974, and grew up with six brothers and six sisters. Miguel, older than him by four years, began working for a gang of smugglers called Los Tejas, who took advantage of proximity to the US border to traffic contraband into the US. This skill, plus his fluency in English, brought him onto the radar of Osiel Cardenas, head of the Gulf Cartel. Soon the family was all working for the Gulf leader.

But in 2010, they split from the Gulf Cartel and formed the Zetas.

Mike Vigil, a former DEA operative, said that Omar publicly boasted that while Miguel may have killed 2,000 people, he had killed 1,000 others.

"Omar is as ruthless and violent as his brother," said Mr Vigil, as the time of Miguel's capture. "I don't think he's as intelligent. But he's capable enough to control the Zetas. He learned from Miguel."

His capture leaves a potential void at the head of the cartel, with no obvious successor.

Servando 'La Tuta' Gomez boards a helicopter during a press conference about his arrest (Rex)

While most of his contemporaries rose to prominence behind the scenes, Servando Gómez Martínez, a former teacher, did so luxuriating in the spotlight.

The 49-year-old made himself a YouTube star, publishing rants justifying his cartel's operations, or giving interviews in hideouts to the media. He relentlessly baited the government, accusing it of colluding with rival gangs while defending his Knights Templar as a "necessary evil".

"Our only function is to help the people, preserve our state, and preserve our country from people causing terror," he said in a video posted online in 2012, sitting in front of images of Che Guevara and other revolutionary icons.

Gomez insisted the quasi-religious cartel followed a strict ethical code, though as time passed he became more open about the criminal side of a gang which in 2013 held much of the impoverished, mountainous landscape of Michoacan in a firm grip.

The local population, however, grew tired of his Knights Templar cartel, and turned against them - with vigilante groups forming, and some helping the police to track him down.

Battles between vigilantes and the Knights Templar turned Michoacan into one of the bloodiest states in Mexico.

Vicente Carrillo Fuentes was following in his family's footsteps when he began a life of crime - his uncle Ernesto Fonseca Carrillo, known as Don Neto, was an infamous drug traffickers in the 1970s, and his brother Amado was known as "Lord of the Skies" for his fleet of 27 planes which he used to transport cocaine from Colombia to Mexico.

Amado recruited Vicente and two other brothers into the trade, under the tutelage of Uncle Ernesto. And the Carrillo Fuentes brothers made the Juarez cartel one of the most profitable in Mexico, controlling the town of Ciudad Juarez which sits just over the border from the Texan town of El Paso.

The area is estimated to be the route of passage for as much as 70 per cent of the cocaine entering the United States.

Amado died in 1997 during a botched plastic surgery operation, which forced Vicente to take over. Under his rule, as the rival Sinaloa cartel fought for control of Ciudad Juarez, the city was transformed into the most violent in the world, with the death toll rising from about 300 murders in 2006 to more than 3,000 in 2010 - a 1,000 per cent increase.

"The outcome of this battle became evident in 2011, when homicides began to drop," said an analysis in Insight Crime. "This year, homicides are near where they were in 2006. The predominant explanation for this reversal: Chapo beat the Viceroy."

At the time of Carrillo Fuentes's arrest, the Juarez cartel was a spent force. However, the 55-year-old had a $5m reward on his head from US authorities, and a similar bounty of about $2m was offered by Mexican prosecutors for information leading to his capture.

Héctor Beltrán Leyva was seized in broad daylight, taken by marines as he ate fish tacos in a seafood restaurant in central Mexico.

He had made his name within the Sinaloa cartel, before he and his three brothers split from the organisation in 2008 and founded their own group. But doing so unleashed a vicious turf war.

The Beltrán Leyva family accused Chapo Guzmán, head of the Sinaloa cartel, of engineering the arrest of the youngest brother, Alfredo. Arturo Beltrán Leyva, the group’s leader at the time, was then taken down by the army in December 2009, dying in a hail of bullets alongside a handful of his bodyguards. Carlos, the lowest-profile of the four, was arrested four weeks later.

That left only Héctor, who took over leadership of the remnants of the core group as it fought another bitter battle against other factions.

In later years he adopted the persona of a wealthy businessman, living relatively openly in Quéretaro.

His arrest effectively ends the cartel's operations, with the routes they controlled being adopted by other groups.

El Chapo

• Joaquín Guzmán Loera• Found: February 22, 2014• Cartel: Sinaloa• Now: Escaped from Altiplano prison on July 11, 2015; on the run

Born Joaquín Guzmán Loera, he grew up in rural poverty in the Sierra Madre mountains, but went on to amass a $1 billion fortune and feature on Forbes' list of richest people. The Sinaloa cartel he headed was said to be active in 50 countries. For 13 years he had evaded capture; the one time he was detained, he escaped, bribing guards in 2001 to let him out and hiding in a laundry cart to flee.

But unlike his younger rivals or Pablo Escobar - to whom he is often compared - Chapo did not flaunt his wealth in glitzy nightclubs or on social media. He kept a low profile, avoiding telephones or email, and lived in the region he was born, protected by locals who shared his wealth. Few ever knew where he was.

Even by the standards of Mexico's drug lords, Miguel Treviño Morales stood out for his viciousness.

The leader of the Zetas, he revelled in violence - murdering 72 migrants in 2010 by the side of a road, leaving his decapitated victims on bridges as a warning to others, and organising the 2011 Monterrey casino attack, which killed 52. His speciality was what he termed "making stew": putting people into oil drums and setting them on fire.

Before he took over control of the cartel, he had been one of their most notorious henchmen, sent to Guatemala to wipe out rivals. His success saw him be promoted within the ranks, and when Zetas leader Heriberto Lazcano, Z-3, was killed in 2012, Treviño Morales was waiting in the wings.